I think the reason newer phones don’t have removable batteries is mainly greed: the battery wears out long before the phone itself stops working.
It’s planned obsolescence beyond what was previously achievable.
Even non-removable batteries can be replace. It’s not a self service item.
Just saw this interesting story out of Europe:
European Union votes to bring back replaceable phone batteries
https://www.techspot.com/news/99102-european-union-votes-bring-back-replaceable-phone-batteries.html